Physical and Chemical Properties of Pine Barks Used As Root Medium Components in Korea, Poster Board #169

This study was conducted to investigate the physical and chemical properties of ground aged pine bark (GAPB) and ground pine bark (GPB) which are commonly used as root medium components in Korea. The GAPB collected was naturally aged in a pile for a year then ground with hammer mill. The GPB was not aged but ground with hammer mill. The total porosity, container capacity, air-filled porosity and bulk density (BD) of GAPB were 78.8%. 42.0%, 37.0% and 0.19 g·cm^-3 whereas those of GAP were 81.3%, 42.0%, 36.8%, and 0.16 g·cm^-3, respectively. The percentage of easily available and buffering water in GAPB were 35.0% and 34.6%, respectively, which were a little lower than 36.6% and 40.8% in GPB. While the GAPB and GPB had similar pH (4.94 vs. 4.86) and electrical conductivity (EC) (0.55 dS·m^-1 vs. 0.50 dS·m^-1), respectively, they showed differences in cation exchange capacity (CEC) (9.32 meq·100g^-1 in BAPB vs. 15.7 meq·100g^-1 in GPB). The concentrations of exchangeable cations in GAPB were Ca 0.32, K 0.05, Mg 0.27 and 0.12 cmol+kg^-1, whereas those in GPB were Ca 0.28, K 0.08, Mg 0.25 and 0.09 cmol+kg^-1, respectively. The soil sap concentrations of PO₄-P, NH₄-N, and NO₃-N were 1,305, 5.42 and 1.13 mg·L^-1, in GAPB and 486, 0.62 and 0.91 mg·L^-1 in GPB, respectively, when analyzed by the saturated paste extraction method. The ash contents of GAPB and GPB soil extracts were 27.3% and 7.7%, respectively. The cold water-, hot water-, and alkali-extracts were 15.0%, 18.7%, and 17.2% in GAPB and 7.7%, 13.0%, 14.0%, 19.5% in GPB, respectively. Additional information in physic-chemical properties of the two root substrates will also be presented.